I have put a magnet over my laptop and I got the error with the file with a ? on it.
I don't have a Time Machine backup or anything. I am not able to reset the Mac and I can't reinstall macOS as it doesn't recognize the HDD. I have tried internet recovery.

MacBook Pro 2011 early is my model.

  • 2
    Sounds to me like the magnet corrupted the data on the HDD. Depending on how important the files are you would want to get help from a professional recovery company. Anything you do from now on with this Mac will decrease the chance of data recovery.
    – X_841
    Commented Mar 17, 2021 at 11:30
  • How strong was the magnet?
    – lhf
    Commented Mar 17, 2021 at 15:52
  • 1
    A 10-year-old laptop hard drive is well beyond its natural life, and could fail at any time. Not having a backup for an ancient hard drive that you're waving magnets around is reckless. I hope that you'll be able to recover your files and learn the importance of backups.
    – benwiggy
    Commented Mar 18, 2021 at 8:01

2 Answers 2


Damage from magnets is hardly possible

However, hard drives can be damaged by extremely strong magnets, but this is much more likely when the hard drive is in use. Typically, a hard drive is also difficult to access without removing it from a computer, so the chance of accidental magnetic damage to these components is very low. And if, for example, the read / write head is damaged, the quality of life is lower but the data is not gone

CRT monitors and televisions are also easily damaged by magnets, but the technology these devices use is extremely out of date and most people now own a plasma or LCD TV.

Except floppy disk

3.5 Floppy disks have a certain amount of magnetism, so proving that magnets can destroy data on floppy disks has reinforced the myth that magnets can also destroy components in a computer. However, if you buy a cheap magnet and place it near a floppy disk, the magnet will stick to the floppy disk and after a few seconds the information on that disk will be destroyed. You will then no longer be able to access the data.

Other storage media

In general, newer storage devices will not be affected by magnets as they have no magnetism of any kind. Although many computers, hard drives, and other storage devices have electrons in them, a normal magnet does not have the power to interfere with these electrons. This also applies to today's memory cards and flash media.

Not magnetic media

Optical media such as CDs, DVDs and Blu-ray Discs do not use magnets to read or write data, and the same applies to flash media such as memory cards, USB sticks and solid state drives (SSDs), which is why magnets cannot cause data loss on these storage media.

If you do not have a T2 security chip and FileVault activated, it is easier to rescue the data. If you say that your hard drive is defective and your Mac cannot start and you want to recover your data, you may want to try connecting that hard drive to another Mac and try "First Aid".

Doesn't it help? Check with a hard drive recovery company that specializes in data recovery.


If your drive is formatted with HFS+ and not APFS, you may be able to use DiskWarrior to repair your drive enough to use Target Disk Mode to extract your data through another Mac onto another disk. However, if the magnet damaged the partition table, or primary and alternate volume headers, or too much of the catalog & extents files, DiskWarrior may not be able to help. In that case you may have to use a professional recovery service like DriveSavers or face the music and start over.

In any of the above situations, once you've gotten your data recovered (or decided not to), you will need to do a full erase & install of macOS. You can do this by creating a bootable installer on another Mac.

  • you can also use internet recovery to install macOS on a Mac with no file system Commented Jan 13, 2022 at 1:02

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